: The string of characters you've provided looks like a hash or a unique identifier used by download managers or software updates. If the file has no extension (like .pdf or .zip), your operating system won't know which program to use to open it.
: Right-click the file and select Properties (Windows) or Get Info (Mac) to see if there is any metadata about the "Type of file" or "Description". Archivo de Descarga yyyyyyy666660BBAF4E60ED8E24...
If this was part of a specific download from a website, try to see if it completes with a proper name and extension. : The string of characters you've provided looks